As if the looming battles over the budget and debt ceiling are not enough, President Obama faces another delicate act with Congress.

INSKEEP: This one too grows out of the Constitution's separation of powers. The president gets to name his cabinet choices - as he's been doing. The Senate gets to confirm or reject them.

MONTAGNE: Some, like Defense secretary nominee Chuck Hagel, face sharp questions. Others, like the Treasury secretary nominee, Jack Lew, would normally face no hostile questions at all. But these are not normal times.

NPR's Tamara Keith reports on the president's latest nomination and what happens now.

TAMARA KEITH, BYLINE: Jack Lew is a life-long public servant and budget wonk. He was a young congressional staffer involved in the 1986 tax reform, served two stints as the chief presidential budget writer - first under President Clinton and then in the Obama administration, and for about the last year he's been president's chief of staff.

PRESIDENT BARACK OBAMA: Under President Clinton he presided over three budget surpluses in a row. So for all the talk out there about deficit reduction, making sure our books are balanced, this is the guy who did it, three times.

KEITH: On the lighter side, the president did say there was one issue with the nominee whose signature would grace the nation's paper currency. That signature looks kind of like the squiggle on top of a Hostess cupcake.

OBAMA: Jack assures me that he is going to work to make at least one letter legible in order not to debase our currency, should he be confirmed as secretary of the Treasury.

KEITH: Notice the phrase should he be confirmed. Throughout most of history, confirmation of cabinet level nominees was more a formality than anything else. Certainly there would be no doubt about someone like Lew, already confirmed multiple times. But now it's not so clear.

Republican senator from Alabama Jeff Sessions put out a scathing statement saying Lew must never be secretary of the Treasury, and calling him the architect of two of the worst budgets in American history. Lew is also getting some criticism from the left for a brief stint at Citibank. And it only takes one senator to put the brakes on a nomination, or at least to slow it down.

Sarah Binder is a professor of political science at George Washington University.

SARAH BINDER: Well, I mean it's just sort of emblematic of senators pushing their powers here, right, into an area where we've traditionally said that senators are willing to defer to the president.

KEITH: It's not clear yet whether this is all bluster or whether senators will end up filibustering one of the president's nominees.

Tevi Troy, a senior fellow at the Hudson Institute, traces this back to the failed Supreme Court nomination of Robert Bork - who was defeated not because of ethical or personal failings, but because of policy disagreements.

TEVI TROY: And when the Senate Democrats scored that scalp, there was thoughts on both sides of the aisles going forward that this was an effective method.

KEITH: Troy, who was deputy secretary of health under President George W. Bush, knows all about the sometimes lengthy confirmation process. He ultimately got unanimous Senate confirmation, but he says it took...

TROY: Longer than it should have, but overall it took less time than most folks. I figure I got it in about four and a half months.

KEITH: But he says it really has been different with top level cabinet positions.

TROY: Cabinet slots are definitively more protected even today in this more contentious environment than other slots. Other slots are much more likely to be held up.

KEITH: Still, there's a question. In fact, two years ago a Democratic senator held up Lew's confirmation to be director of the Office of Management and Budget for two months - over an unrelated policy disagreement. Which might explain why with each announcement President Obama calls on the Senate to move quickly.